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Continuing Education
Adrian Parnaby-Price, MA, MB, BChir, (Cantab), FRCSEd
The College of
Optometrists
sponsored by
Clinical decision making
in ocular emergencies
The optometrist is the first professional contacted by many people
suffering acute ophthalmological conditions. It is, therefore,
important that these are recognised and managed effectively,
especially those conditions in which prompt treatment has the
potential to significantly improve the outcome.
The key to management of ocular
problems, and especially in emergencies,
lies in the successful diagnosis of the
condition. Unfortunately, even in
specialist ophthalmic centres, the
precise diagnosis is not always possible
but recognition of features and patterns
often suggest the nature of the problem
and are usually enough to guide the
basic management. Whilst specific areas
are covered in other parts of this series
(e.g. the red eye), the aim of this article
is to suggest features of the presentation
which will be of help in reaching a
diagnosis upon which management of
specific emergencies can be undertaken.
HISTORY
The limited range of symptoms
pertaining to the eye means that most
ophthalmic histories are fairly brief.
Despite this, there is often enough
information to provide clues to the
underlying pathology or to exclude
others. Hence, the history of a sudden,
painless loss of vision in an older patient
known to be on medication for high
blood pressure tends to imply a vascular
cause rather than an inflammatory one.
Pre-existing disease
It is always useful to start the history
with a brief question about the eyes
before the onset of the presenting
problem. Previous amblyopia, uveitis or
ocular surgery might influence
subsequent management.
General health
Of particular relevance to ophthalmic
problems are systemic conditions which
are associated with ocular disease,
particularly cardiovascular conditions
(associated with cerebrovascular
accidents and retinal vascular occlusion)
and generalised inflammatory conditions
(associated with uveitis and scleritis).
Many patients are surprisingly reticent
about previous illness which they do not
consider might be related to a problem
with the eye and few volunteer a
comprehensive list. It is wise to
formulate a rapid system to work through
this area. A general question to begin
might be - “Apart from your eyes are you
well?” followed by a specific series of
questions to run through disease
associations, for example, “Do you have
high blood pressure or diabetes; have you
had any heart attacks or strokes; have
anything wrong with your joints, bowels,
heart or lungs?”. In cases where there is
little history forthcoming or the
converse, where a potentially complex
history begins to emerge, it is also wise to
ask for details of any medication. “Do
you take any tablets, pills, puffers,
patches or injections for anything?” -
may rapidly summarise the kind of
medical problems which are currently
active and serious enough to require
regular treatment.
PRESENTING COMPLAINT
This can often be summarised concisely
into: 1) whether the vision is affected or
not, what is the nature of any visual
problems and what degree of visual
impairment exists; 2) whether the eye is
painful; 3) whether the eye is red; and 4)
the speed of onset and duration of any
symptoms (sudden, rapid, slow). This is
actually entirely adequate for the
assessment of the majority of cases and it
is unusual to find ocular problems which
require more detailed questioning or
which, once a painstaking history has
The College of Optometrists has awarded
this article 2 CET credits. There are 12
MCQs with a pass mark of 66%.
been taken, cannot be summarised in
this form. Remember that the physical
findings are often more important in
determining the management which is
the end-point of a consultation, and that
certain points can be reviewed after the
examination.
Particular features of a history which
might be important in diagnosis and
management are:
Visual acuity
This is often the reason for seeking a
consultation and may be described in a
variety of ways by the patient. ‘Blurring’
of vision has been use to describe almost
any degree of visual impairment from
distortion with no loss of Snellen acuity
to perception of light. Always try to get
an accurate description of the
impairment: can the patient still read,
watch television, drive a car safely? Is the
description simply a reduction in acuity
or is the patient describing loss of a part
of the visual field? The degree of loss may
in itself aid differentiation but large
visual field defects may cause serious
disability and yet still allow a good
Snellen acuity. Occasionally, visual loss is
transient, in which case it is important to
get a detailed description about each
occasion when vision has been lost.
What exactly was the patient doing
when the vision went and how quickly
did it go; how long was it gone for and
how bad was vision at its worst; how
quickly did it return? For example,
transient occlusion of the vertebrobasilar
artery during extreme neck
movements might affect vision only
when driving.
Distortion of vision
Conditions altering the anatomy of the
fovea, such as oedema or sub-retinal
neovascularisation, cause distortion of
the retinal photoreceptor position and
this has secondary effects on vision. In
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more severe distortions, straight lines
become bent or kinked (door frames are
often among the first objects to be noted
as affected). Retinal oedema causes the
photoreceptors to be displaced apart
from each other and the patient
experiences micropsia where the same
size retinal image falls upon fewer
photoreceptors and is, therefore,
interpreted as being smaller than in the
fellow eye. This symptom is, therefore,
highly suggestive of foveal pathology and
may be reliably documented with an
Amsler chart.
Pain
This is a feature of a variety of conditions
but, when linked to other parts of the
presenting problem, can be important in
establishing a diagnosis. A foreign body
most commonly gives rise to a pricking
sensation and uveitis is more commonly
described as an achy pain with specific
exacerbation in light (photophobia). The
lack of pain might be important as
retinal detachment and vascular events
are painless despite profound visual
disturbance.
Discharge and tearing
Surface problems, such as conjunctivitis
and foreign bodies, cause irritation and
activate defence mechanisms to give rise
to increased secretions. Whilst a watery
discharge in a case of conjunctivitis
might suggest a diagnosis of viral, as
opposed to bacterial, conjunctivitis in
which the discharge is more purulent, it
is important to put this feature into its
full clinical context. A watery,
discharging eye is a feature of many more
conditions including severe immune
conditions of the sclera in which
perforation of the globe is a possibility
and a full history and examination is
imperative.
Flashing lights and floaters
Together, these are symptoms of a
posterior vitreous detachment which is
the mechanism by which holes are
formed in the retina leading to a retinal
detachment. Floaters alone might
indicate inflammation in the vitreous
and may be symptomatic only during
reading. Because of the paucity of
symptoms from even a large retinal
detachment, these apparently trivial
symptoms should always be treated
seriously as a potential emergency and
mean that a peripheral hole must
specifically be excluded at examination
which cannot be done without pupil
dilation and indirect ophthalmoscopy.
Specific history
Always consider the possibility of
trauma, although this is not always
straightforward. Several days can elapse
between metallic foreign bodies entering
the eye and the onset of symptoms and
some patients (especially children) may
be unwilling or unable to admit to
accident or assault. Chemical injury to
the eye must be specifically considered
and excluded. Contact lens use
represents a particular risk for keratitis
and, if lenses are implicated in the
complaint, it is important to ensure that
the daily routine is established,
particularly patterns of wear and
sterilisation methods. All lenses, cases
and solutions should be available for
microbiological examination if possible.
EXAMINATION
Whilst the history of the problem may
be sketchy or brief, the key to diagnosis
is often the pattern of pathology based
on the findings of the clinical
examination and the diagnosis may
become clear within moments. Even
quite complex neuro-ophthalmological
conditions may be successfully
diagnosed despite the absence of
findings in the eye. This part of the
consultation is, therefore, very
important and needs to be undertaken
systematically. Attempts to skip a
complete assessment from the outer
eyelids and lashes to the retina and discs
will mean that clues may be missed.
Visual acuity
The first part of the examination must
be the visual acuity in each eye both
unaided and best corrected or using a
pin-hole. Whilst it is occasionally
overlooked in a busy practice, especially
if pathology is clearly identified from the
outset, it is important to ensure that on
every occasion it is recorded clearly in
any notes. Acuity is sometimes the most
useful guide to the differentiation
between minor problems and more
serious pathology and is considered a
critical part of any legal analysis of
medical notes.
Colour vision
This is a measure of higher processing
functions but, in severe problems, the
more useful guide is subjective
sensitivity to red targets. In the early
stages of optic nerve disease, there is a
perceived reduction in the brightness of
a red target such as a pen top. In
conditions such as acute thyroid eye
disease or orbital cellulitis, in which
there is rapidly increasing orbital
pressures and optic nerve compression,
loss of acuity is a late sign and nerve
swelling occurs even later (by at least 24
hours).
Visual fields
A further aid to the diagnosis is the
visual fields. In an emergency setting,
simple patterns are often all that is
required which may be performed with a
red target such as a hat-pin without
complex automated perimetry. The aim
is to identify which part or parts of the
visual field are affected and it is vital to
ensure that the fellow eye is examined as
well. There are a number of classical
patterns of visual field loss but the
overwhelming majority of patients fit
into one of only a half-dozen or so.
It is simple to consider each field as
consisting of only eight areas (Figure 1).
Each is ‘normal’, ‘impaired’or ‘lost’. Any
findings are, therefore, clearer and can
more easily fit a pattern such as
hemianopia, unilateral loss, etc.
The next important features of the
defect are whether it extends to central
fixation or not and whether the defects
are centred on the blind spot (suggesting
optic nerve disease or larger retinal
vascular problems) or horizontal and
vertical meridia (bilateral mid-line
patterns are generally post-chiasmal and
in the brain).
Common patterns and potential
diagnoses include: 1) Hemianopia;
usually homonymous (Figure 2),
suggesting cerebrovascular accident
(CVA, stroke) involving the optic
radiations or occipital cortex; may be
bitemporal (Figure 3) suggesting a
lesion at the optic chiasm; 2) gross loss
of one field centred on blind spot
(optic nerve involvement such as optic
neuritis or optic nerve tumour) (Figure
4); 3) quadrantanopia (Figure 5) (CVA
in either temporal or parietal lobe where
superior and inferior fields have different
pathways); 4) central hemianopia
(Figure 6) (occipital cortex tip lesion);
5) hemianopia sparing central vision
(Figure 7) (occipital cortex lesion with
sparing of occipital tip); and 6)
altitudinal defect (Figure 8) (branch
retinal artery or vein occlusion).
In cases of CVA or tumour-related
disease, there may be other signs to aid
diagnosis, such as cranial nerve lesions,
which should be considered.
Ocular examination
In an attempt to reach a rapid diagnosis,
it is important not to miss any ocular
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Figure 1
Basic visual fields showing 8
areas and blind spot
Figure 2
Homonymous hemianopia
respecting fixation - CVA
affecting optic radiations
Figure 3
Bitemporal hemianopia
- chiasmal lesion
Figure 4
Loss of one complete visual
field - optic nerve disease
Figure 5
Quadrantanopia
- temporal lobe CVA
Figure 6
Central hemianopia
- occipital cortex tip lesion
Figure 7
Hemianopia sparing central
vision - occipital cortex
sparing tip
Figure 8
Altitudinal defect - inferior
branch vascular occlusion
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features which may assist diagnosis or
management. It is wise to consider the
history and symptoms when trying to
identify pathology but, at the same time,
each part of the eye should be
systematically considered. Even in the
most dramatic cases, consider first the
eyelids, then the conjunctiva, cornea,
anterior chamber, iris and pupil, vitreous,
retina and disc individually. Always
perform a careful assessment of the pupils
for an afferent defect which will indicate
optic nerve disease. A relative afferent
pupillary defect may be present in eyes
with normal vision, although the reaction
will not be present when both optic nerves
are equally damaged. The intraocular
pressure (IOP) must be measured before
dilation, even in apparently
straightforward cases. Testing the IOP and
the pupil are vital in the assessment of
patients. For example, in a case of retinal
vascular occlusion, the IOP and the
presence or absence of an afferent
pupillary defect at presentation are key
points in the subsequent management. If
the patient is already dilated, these cannot
be reliably re-assessed.
In assessing a red eye, the green light
filter on the slit lamp should be used. This
has the effect of bringing the red vessels
into much sharper relief by removing
discoloration and allows a much clearer
identification of which layer is injected
(i.e. conjunctiva, episclera or sclera).
Non-ocular signs may exist such as
swollen pre-auricular lymph nodes in viral
conjunctivitis and cranial nerve lesions.
INVESTIGATIONS
These are based on the clinical findings
and are often aimed at non-ocular
associations.
Imaging ultrasound, X-rays, MRI
(magnetic resonance imaging) and CT
(computerised tomography) scans are
useful and widely available techniques to
allow detailed examination of non-visible
tissues. B-scan ultrasound is safe and
widely used in ophthalmic departments. It
is most useful in imaging eyes in real-time
for vitreous haemorrhage and scleritis of
the posterior globe (which is seen as
thickening and increased signal return).
X-rays are still widely used to identify
sinusitis and breaks in the zygoma and
orbital floor following trauma, although
MRI and CT scans are often preferred. CT
scans are currently fairly cheap and widely
available and allow identification of bony
and soft tissue lesions in the orbits and
skull. MRI scans tend to be better for
imaging some lesions, particularly
demyelinating lesions (multiple sclerosis
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lesions). MRI cannot, however, be used
in those patients with magnetic metals
such as steel in the field being examined
as it causes movement and heating of the
metal. Any suspected foreign body
should be considered when selecting the
method of imaging.
Microbiology
The isolation of an organism as part of
the management of ocular infection is
not always critical if it is mild and
responds to conventional treatment. In
conjunctivitis, most cases are likely to be
self-limiting and conjunctival swabs are
rarely sent. Bacteria can be seen in small
numbers on swabs after brief processing
has been performed to allow a rough
guide as to the kind of organisms
involved and, if requested,
microbiological departments can
comment on swabs within hours. Specific
antibiotic sensitivity will not be available
for several days after samples are taken
which is usually too late to influence
initial management.
Wherever possible, samples should be
taken before any antibiotic treatment is
instigated and unpreserved analgesic
drops used as required to allow corneal
scrapes. If treatment is already in
use (including over-the-counter
preparations), details should be
forwarded to the microbiologist with the
sample.
Viral swabs have to be transferred
into cultured cells to allow replication
and subsequent identification which
takes several days and prevents rapid
identification. In suspected viral
infections, serology of the patient’s
changing antibody levels in response to
the infection may be the only way to
identify the virus.
Particular cases, where identification
of the organism is crucial, include
endophthalmitis and acanthamoeba
keratitis where prolonged and intensive
treatment will be required with
implications for the prognosis. In
contact-lens related infection, the lenses,
case and cleaning solutions should be
sent for analysis.
Blood tests
Many of these are for systemic
associations of ocular pathology and are
focused about specific diagnoses. In
arterial occlusion, the most important
differential diagnosis is between
inflammatory and non-inflammatory
causes and an ESR (erythrocyte
sedimentation rate) and CRP
(C-reactive protein) level is mandatory
(both are non-specific measures of
generalised inflammatory activity but
not diagnostic of specific conditions in
themselves). Vascular occlusions
generally require blood counts for
clotting predispositions such as excess
haemoglobin and platelet levels,
inflammatory and clotting diseases and
serum markers for atherosclerosis
(cholesterol and fat levels). Acute
proptosis requires investigations centred
on inflammatory conditions but
especially for antibodies implicated in
thyroid disease (the most common cause
of both unilateral and bilateral
proptosis).
TREATMENT
Comprehensive and detailed
management of individual conditions is
beyond the scope of this article but many
are covered in other articles in the CPD
series. The following are some of the
more common conditions, particularly
those that are potentially serious or in
which effective management may
improve the outcome.
VASCULAR EMERGENCIES
Central and branch
retinal artery occlusion
The most important investigations once
diagnosis has been made are the ESR
and CRP (see above). On this basis,
arterial occlusion is presumed to be
either non-arteritic (thrombo-embolic in
origin) or arteritic (inflammatory in
origin).
Non-arteritic CRAO (Figure 9)
Treatment can be very effective if
administered within 24 hours of onset
and hinges around attempts to dislodge
the embolus to the retinal periphery
where loss of blood supply will cause
limited damage to the vision. This is
achieved in the first instance by globe
massage in much the same way as a
plunger is used on a blocked domestic
pipe. The patient closes the eye and two
fingers are used to press on the closed
lids firmly and continuously for around a
minute to build up the intraocular
pressure. The fingers are then suddenly
removed to drop the IOP rapidly and
dislodge the embolus. The process is
repeated at one-minute intervals and
can be continued en-route to the nearest
ophthalmic unit. Some authorities
advocate a firm rubbing of the closed eye
to achieve a similar fluctuation in IOP.
Steps are subsequently taken to reduce
the pressure opposing arterial blood flow
Figure 9
Central retinal artery occlusion with cherry red
spot. Note a cilioretinal artery preserving a
small area of normal retina adjacent to the
disc for comparison
(the greatest and most flexible
component of which is, again, the IOP)
and help to push the embolus further
along the vessel. IOP may be reduced by
pharmacological means including
conventional glaucoma medication and
acetazolamide and can be reduced by
breathing higher levels of carbon
dioxide. This causes venous dilatation
with a fall in back-pressure and this is
most easily achieved by asking the
patient to breathe in and out of a paper
bag. IOP may be most rapidly and
efficiently dropped by anterior chamber
paracentesis. This entails sitting the
patient on a slit lamp and anaesthetising
the eye with topical drops before a fine
needle mounted on a syringe without a
plunger is inserted into the anterior
chamber through the limbus. 0.1-0.3ml
of aqueous is removed before the needle
is withdrawn and, because fluid is not
compressible, IOP falls profoundly.
Management in the longer term is to
maintain a low IOP and to treat
underlying risk factors such as
atherosclerosis, hypertension and, in
some cases, oral anti-coagulation with
aspirin or warfarin.
Arteritic (inflammatory) CRAO
Whilst producing a similar ocular picture
to embolic disease, inflammation of the
arterial walls also produces retinal artery
occlusion. This is a process similar to
arteritic anterior ischaemic optic
neuropathy (see over).
Anterior ischaemic optic neuropathy
This is the occlusion of the posterior
ciliary arteries causing infarction of the
optic nerve head. Visual loss is rapid and
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Figure 10
New vessels at the optic disc in severe
diabetic retinopathy
Figure 11
Vitreous haemorrhage from disc new vessels
profound and irreversible with an early
relative afferent pupil defect. Although
anecdotal reports exist of partial visual
loss and of some recovery of vision, this
is unusual and a history of intermittent
loss of vision should suggest a different
diagnosis. As in CRAO, two variants are
recognised, non-arteritic and arteritic.
Non-arteritic AION
This is probably a variant of CRAO with
atherosclerosis as the underlying
associated or causative pathology.
Management is similar to CRAO with
reduction in IOP, aspirin and anticoagulation
as therapeutic options in the
acute phase and management of
atherosclerotic associations in the
follow-up period.
Arteritic AION
(and arteritic CRAO - see above)
This is most commonly associated with
temporal arteritis. This condition almost
exclusively affects the over-70s and cases
under the age of 55 are rare. Temporal
arteritis is associated with polymyalgia
rheumatica in which there is usually a
long history of non-specific illness,
weight loss, pain, wasting and weakness
of muscles of the upper legs, upper arms
and shoulders with difficulty in raising
the arms above the shoulders to brush
the hair. Temporal arteritis also causes a
tender scalp and jaw claudication
(progressive weakness and pain on
chewing). Blood tests characteristically
reveal a very high ESR and CRP and
biopsy of the temporal artery provides
typical changes of inflammation in the
walls of the vessel. Surgical biopsy of a
section of the temporal artery is the most
accurate diagnostic test of temporal
arteritis. Initial management is with very
high doses of intravenous steroids and
maintenance on oral steroids at a high
dose for several weeks with a gradual
reduction over not less than 1-2 years.
Few reports exist of any recovery of vision
in the affected eye despite rapid
treatment, but the aim is to preserve the
second eye and prevent spread to other
arteries such as the basilar artery in the
brain with secondary, usually fatal
cerebrovascular accident. Generalised
symptoms of polymyalgia rheumatica and
temporal arteritis rapidly improve on
treatment.
Central and branch
retinal vein occlusion
The acute management of vein
occlusions is aimed at reducing the
tendency to form thrombus and to
increase venous drainage from the retina.
Acutely investigations need to exclude or
correct high levels of haemoglobin or
platelets and any fluid deficit. Other
factors which need to be specifically
addressed are those tending to thrombus
including oral contraceptive use in
women and other conditions affecting
clotting. Current opinion is divided as to
whether anti-coagulation is of benefit in
the acute phase as the retinal picture is
haemorrhagic and could potentially be
worsened. After three months oral
aspirin, which selectively reduces platelet
activity, is widely used although the dose
at which benefit may occur is uncertain.
In the longer term, trials to reduce
haemoglobin levels by isovolaemic
haemodilution in patients fulfilling
certain criteria have produced scant
evidence that this may help but this
technique is not widely used.
Vitreous haemorrhage
This usually presents with a painless loss
of vision although it may be associated
with ocular trauma. There is usually a
specific cause for the haemorrhage which
include new vessels from diabetes
(Figure 10 and 11), an old retinal
vascular occlusion and from posterior
vitreous detachment with avulsion of a
retinal vessel. Whilst the haemorrhage
will clear spontaneously with time, the
biggest problem arises from the potential
for progression of other pathology. All
cases should be managed as a potential
retinal detachment identified by
ultrasound of the eye or by indirect
ophthalmoscopy. Such cases may need
vitrectomy to clear the haemorrhage
before proceeding to management of
associated problems.
Cerebrovascular accident
(CVA, stroke)
This is the result of problems with the
blood supply to the brain and is usually
the result of atherosclerosis. There are
two main types: ischaemic, in which
vessels either tend to occlude (with loss
of the blood supply to the brain); and
haemorrhagic when vessels bleed into
the tissue of the brain. A third type is the
transient form in which symptoms
resolve within 24 hours and which are
considered to be due to small emboli
(transient ischaemic attacks - TIAs).
The exact clinical picture depends upon
the site of the problem but can produce a
bewildering variety of symptoms and
signs. Presentations include single or
multiple nerve palsies of any of the
ocular and associated nerves and
particular patterns of visual field loss
including hemianopias, quadrantanopias
and, occasionally, loss of only small parts
of field around fixation or central vision
(due to lesions at the tip of the occipital
lobe). Many neurological problems may
be apparent from a good history and
clinical examination (especially of visual
fields) and require urgent investigation
and management firstly to reduce risk
factors for CVA and also to exclude
other causes of neurological damage such
as intracranial tumours, abscesses and
inflammatory conditions involving the
brain.
TRAUMA
Most traumatic conditions will require
specific surgery to correct the injury but
in all cases of trauma, the principal
maxim is to fully elucidate the nature
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and extent of any injury by adequate
examination and to fully plan surgery or
other management. In unco-operative
patients (particularly in children) a
general anaesthetic may be required. In
other cases, unpreserved anaesthetic
drops are considered safe following
penetrating injury (and are used without
retinal toxicity in ocular irrigating fluids
during surgery) and may be used as
required to facilitate examination. The
risk of infection after penetrating injury
is actually surprisingly small but the
administration of systemic antibiotics
prior to surgery is the main adjunct.
Topical antibiotics appear to convey no
significant effect on reducing
endophthmitis.
Corneal abrasion
This is excruciatingly painful in younger
patients with symptoms out of
proportion to the apparent injury.
Always consider more serious injury and
possible globe penetration during
examination. Dilation of the pupil is an
extremely effective analgesic and many
authorities commend pressure patching
until re-epithelialisation has occurred
with consequent reduction in pain. Do
not patch an eye unless it is taped shut or
a lubricated gauze is placed next to the
eye in case an abrasion is caused by the
dressing. Many patients find a pressure
dressing uncomfortable and consider an
unpatched eye preferable and use ice
packs with some relief. Rarely the
epithelium fails to heal in which case
deliberate removal of the epithelium to
allow a fresh attempt is usually effective.
Recurent corneal erosion
This may follow an abrasion, sometimes
months later, and presents typically with
a patient awaking during REM sleep.
Rapid eye movement is thought to
spontaneously abrade the corneal
epithelium with similar extreme pain,
although it is usually on a smaller scale
and has often healed by the time the
patient is examined on a slit lamp with
obvious diagnostic problems. Most cases
resolve with the use of topical lubricants
applied last thing at night or epithelial
debridement.
Chemical injury
Chemical injury requires an immediate
response with removal of the material
with forceps if appropriate followed by
irrigation with saline or water. Topical
anaesthesia should be used as required to
permit examination and irrigation
performed even if penetration is
suspected. Do not accept any history of
previous irrigation at the scene of the
accident as satisfactory - ALWAYS
REPEAT IT YOURSELF
IMMEDIATELY - 30 minutes with 1-2
litres of saline or water is usually required
to produce satisfactory results and the
lids must be everted to ensure that
subtarsal remnants are not missed. Even
where eyewash is available, it is only
rarely in sufficient quantity to be
effective. pH should be checked with
particular caution being exercised if
alkali injury is suspected (high pH) as
alkali rapidly enters the anterior chamber
with signs of ischaemia manifest as closed
vessels at the limbus and corneal
epithelial loss.
If synthetic riot-control agents such
as CS, mace or tear gas have been used,
particular care must be exercised not to
allow contact of health workers with the
clothes of the victim as any remaining
agent can be transmitted with disastrous
results. Again, topical anaesthetic as
required, ocular examination to
determine injury followed by copious
irrigation with water or saline, remains
the recommended treatment. Pain,
inflammation and secondary infection
are treated with topical mydriatics,
steroids and antibiotics as required. As
soon as possible, ensure that no other
ocular injury exists in conjunction.
INFLAMMATORY AND
ALLERGIC EMERGENCIES
Hayfever and atopic disease
Whilst not considered a serious
condition, mild forms of allergy in the eye
are common and constitute a significant
workload to some practitioners. They are
often associated with other allergies such
as asthma and eczema. Severe forms are
difficult to diagnose as they may resemble
more severe inflammatory conditions,
particularly viral keratoconjunctivitis
with corneal infiltrates but the absence of
a swollen pre-auricular lymph node is an
important diagnostic feature. Follicles
(which are usually swollen to form ‘grains
of rice’ in the tarsal conjunctiva in the
acute phase) and more superficial
injection over the globe are also features
of allergy. In extreme cases, lacrimation
occurs under the conjunctiva with
chemosis (Figure 12). Always check the
visual acuity and warn the patient to
re-attend if symptoms persist or worsen.
Figure 12
Conjunctival chemosis in acute allergic eye disease
Figure 13
Acute iritis showing perilimbal injection
Acute symptoms are best controlled with
ice packs and topical antihistamines and
mast-cell stabilisers with topical steroids
reserved for more severe cases.
Anterior uveitis
This has several clinical appearances
with variable amounts of fibrin (flare)
and aggregations of leucocytes in the
aqueous (cells) (Figure 13). The history
is usually of gradual increase in irritation,
redness, photophobia and reduction in
acuity. This can be over several days,
weeks or may be of only a few hours. The
long-term complications of acute
anterior uveitis stem from the deposition
of fibrin and subsequent scar formation
in the trabecular meshwork to produce
glaucoma. Adhesions between the iris
and the anterior lens capsule produce
synechiae with pupil distortion and
obstruction of the flow of aqueous
through the pupil with a risk of pupilblock
glaucoma. Anterior uveitis,
therefore, needs to be suppressed rapidly
before these changes become established.
Firstline treatment is with frequent dose
topical steroids and dilation of the pupil.
APRIL 9 • 1999 OPTOMETRY TODAY 7

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Clinical decision making in ophthalmic emergencies
DISTANCE LEARNING MODULE 1 PART 4
Figure 14
Mutton fat keratic precipitates in granulomatous
uveitis. Associated systemic diseases need to be
excluded
In cases with a high fibrinous
component, or in which synechiae have
already formed, steroids and mydriatics
may be given as a sub-conjunctival
injection to maximise dosage. Intraocular
pressure rises are usually managed with
conventional topical glaucoma therapy.
As the uveitis comes under control,
treatment is tapered but may need to be
continued for weeks or months to avoid
recurrences, which are relatively
common. Unresponsive cases are
infrequent but, occasionally, require
systemic treatment with
immunosuppressive drugs including
steroids, azathioprine and cyclosporin
(potent suppressers of T-lymphocyte
activity, the leucocytes thought to
control the underlying inflammatory
process). Uncomplicated cases which
respond rapidly to topical treatment are
not usually extensively investigated but
mutton-fat keratic precipitates of
leucocytes (which are larger and more
greasy in appearance) are particularly
suggestive of an associated inflammatory
condition (Figure 14).
Posterior uveitis
This tends to present with a more
gradual onset than anterior uveitis with a
gradual, painless impairment of vision
and, in particular, the formation of
floaters. It is potentially more serious as it
may have been active longer prior to
diagnosis and the retina is frequently
directly involved with permanent visual
impairment. Signs of active inflammation
are chiefly the finding of small deposits of
leucocytes in the vitreous and cases
usually require prolonged and intensive
management with systemic
immunosuppressive drugs. There is a
high incidence of associated diseases
including Behçet’s disease, sarcoidosis
and idiopathic retinal vasculitis which
need to be considered.
Episcleritis
This presents with discomfort or usually
mild pain in a watery red eye. There is
usually no impairment of vision and
injection is in a fairly discrete area with
dilation of the finer, more superficial
episcleral vessels and a slight blue-purple
hue to the area. Although attacks are
self-limiting and resolve without
sequelae, topical steroids and oral
flurbiprofen control symptoms and
shorten attacks. A similar condition is an
inflamed pingueculum in which an
episcleitis-like condition is centered on a
pre-existing pingueculum. This responds
to similar treatment and also resolves
without sequelae. Recurrence is common
in both conditions.
Scleritis
This is usually painful and can be
localised to a small, discrete area or be
more extensive. Vision is usually
unaffected and the condition is
associated with other immune disorders
including rheumatoid arthritis. A
variant is posterior scleritis in which
severe pain can be a feature in an eye
which is not red. Secondary oedema may
induce retinal changes with visual
symptoms and occasionally proptosis or
even optic nerve compression. Imaging
with ultrasound, MRI or CT scan reveals
thickening of the sclera. Treatment is
systemic with oral non-steroidal antiinflammatory
drugs (particularly
Flurbiprofen and indomethacin). In
severe cases oral and intravenous
steroids and other immunosuppressives
may be required.
Optic neuritis
Inflammation of the optic nerve is
usually a part of a demyelinating disease
(of which multiple sclerosis is the most
common form). The visual loss occurs
over a few days and is usually profound.
It is associated in the initial stages with a
reduction in sensitivity to red objects and
an afferent pupil defect, and may be
associated with active lesions elsewhere
including the fellow optic nerve. If the
focal lesion is not close to the optic nerve
head, there may be no disc swelling or
other signs of disease. Treatment is
limited with high dose intravenous
steroids used in severe cases but these
seem to offer little or no long-term
benefit.
INFECTIVE CONDITIONS
Conjunctivitis
Bacterial conjunctivitis may be identified
by its mucoid or purulent discharge with
little effect on the visual acuity. Most
cases are self-limiting although cases
caused by Neisseria or Chlamydia may be
persistent and require systemic
treatment for associated sites of infection
(most commonly the genito-urinary
tract). Viral conjunctivitis is associated
with a watery discharge and follicles in
the conjunctiva of the eyelids. A swollen
pre-auricular lymph node (just in front
of the ear on the affected side) is a
common finding. Vision may be affected
if the cornea is also involved, often in a
characteristic pattern of sub-epithelial
opacities (e.g. in adenoviral
keratoconjunctivitis). Most are thought
to be spread by droplets from the nose
and throat of infected individuals and
epidemics are common. There is no
specific treatment for viral infections
(other than for herpes virus) and disease
can continue for several weeks or even
months. Whilst symptoms can be
controlled by treatment with topical
steroids, this is thought to prolong the
recovery time and is usually reserved for
particularly severe cases. Topical
antibiotics are often prescribed to reduce
the risk of secondary bacterial infection
but evidence for their effectiveness is
poor.
Keratitis (including
acanthamoeba, bacterial
and herpetic keratitis)
This is characterised by pain, corneal
infiltrate and epithelial defect. The
keratitis may be infectious (associated
with contact lens use) although other
conditions, including autoimmune
disease, can cause severe keratitis.
Whilst certain patterns of keratitis are
diagnostic (such as herpetic),
microbiological analysis of any infection
from swabs and corneal scrapes guides
subsequent intensive antibiotic
treatment. Topical and/or systemic
immunosuppression is usually required
to control inflammatory causes.
Orbital cellulitis,
sinusitis and dacrocystitis
Bacterial infections in sites adjacent to
the orbit may lead to secondary infection
and patients may present with proptosis
and reduced ocular movements.
Because of the associated swelling, there
is a risk that orbital pressure will rise with
8
APRIL 9 • 1999 OPTOMETRY TODAY

sponsored by
Clinical decision making in ophthalmic emergencies
DISTANCE LEARNING MODULE 1 PART 4
optic nerve compression (see above). A
broad-spectrum antibiotic in high dose
is required but care must be exercised in
dacrocystitis - if the sac is lanced or
bursts through the skin of the cheek, a
fistula may form requiring surgical
correction.
Herpes zoster (shingles)
This is caused by reactivation of the
varicella-zoster virus (which causes
chickenpox) which remains dormant in
a sensory nerve root. Reactivation
occurs in response to alteration in the
immune system with effects in the
anatomy supplied by the particular
nerve involved. Globe and lid sensation
is served by the ophthalmic and
maxillary branches of the fifth cranial
nerve and early symptoms are of altered
sensation or pain over the area
involved. Swelling and pain may
precede the typical skin rash which
produces weeping pustules and appears
around four to seven days after initial
symptoms. Conjunctivitis of
predominantly the upper or lower lid,
keratitis and scleritis are common
features although intraocular
involvement is not common. Entry to
the eye requires involvement of a
sensory branch, the naso-ciliary nerve.
The presence of rash at the tip of the
nose (Hutchinson’s sign) should raise
suspicions and suggest more frequent
review as the uveitis produced can be
insidious and asymptomatic until fairly
advanced. Treatment is with specific
anti-viral drugs to limit the replication
of virus and shorten the attack. There is
also some suggestion that prompt antiviral
therapy can reduce the incidence
of post-herpetic neuralgia. In cases
without intraocular involvement,
recovery is straightforward but
intraocular inflammation requires
intensive topical treatment (see anterior
uveitis) and is prone to relapse. Most
cases require at least nine months of
topical steroid drops.
RETINAL AND DISC CONDITIONS
Retinal detachment
This often presents late and advanced
with extensive peripheral field loss as it
is not until there is loss of macular
function that the patient notices a
definite symptom. Management is to
close any retinal holes and relieve
vitreous traction on the retina to allow
re-attachment by external buckling of
the sclera or by vitrectomy.
Macular oedema
This is a feature of a number of
conditions including diabetes, various
inflammatory conditions of the retina,
scleritis and central serous
chorioretinopathy. This causes a
variable degree of visual distortion and
loss of acuity. Treatment relates to the
diagnosis and may require laser
photocoagulation of areas of capillary
leakage.
Hypertensive retinopathy
Treatment is directed at the
hypertension or the cause of
hypertension but cases are often those in
which hypertension is secondary to other
diagnoses and difficult to manage. The
ocular problems tend to predispose
towards a picture of vascular occlusion
and disc swelling (Figure 15) but
resolve when the blood pressure lowers.
Unfortunately, the more severe cases
often have a poor prognosis with
multiple organ failure.
Swollen optic discs - optic neuritis,
intracranial hypertension
Swollen discs may be due to a number of
causes including optic nerve head drusen
but, in the presence of visual reduction,
headache and other symptoms, need to
be considered as potentially due to a
more serious pathological process. An
MRI or CT of the brain and orbits will be
required to exclude lesions of the optic
nerves such as meningiomas,
demyelinating disease or lesions in the
ventricular system of the brain. Lumbar
puncture is often required to establish
the pressure of cerebrospinal fluid and to
examine it for the presence of
inflammatory cells or proteins.
OTHER CONDITIONS
Glaucoma
Acute closed angle glaucoma causes
damage to the optic nerve and there is a
significant risk of secondary vascular
occlusion. While intraocular pressure is
high, little or no topical medication will
enter the eye and intravenous or oral
acetazolamide is required to cause initial
pressure reduction. Pilocarpine and
other topical glaucoma treatments are
Figure 15
Swollen optic disc in acute hypertensive
retinopathy
used thereafter. In the longer term, YAG
or argon laser iridotomy or surgical
iridectomy is the treatment of choice to
maintain low pressure with a few
patients requiring more extensive
surgery because of irreversible damage to
the angle. Treatment may be delayed
until intraocular pressure is controlled by
medical treatment, as oedema can make
the cornea opaque to lasers and require
excessive power to permit treatment.
Thyroid eye disease
Thyroid eye disease is generally a
chronic problem in which the orbital fat
swells and extraocular muscles fibrose.
This can present with acute proptosis
but less often presents as visual loss
resulting from optic nerve compression.
The condition is rare and requires
systemic immunosuppression, X-ray
treatment and, occasionally, surgery to
the orbit to release the pressure.
CONCLUSION
The key to the optimum management of
ocular emergencies lies in a careful
assessment of the features of the
condition to suggest the general nature
of the problem. This, in turn, will guide
the initial management to allow
appropriate investigations and basic
treatment.
ABOUT THE AUTHOR
Adrian Parnaby-Price is a Fellow in Ocular Immunology at
St Thomas’s Hospital, London, and a Specialist Registrar in
Ophthalmology in the South-East Thames Region.
APRIL 9 • 1999 OPTOMETRY TODAY 9

Multiple choice questions
Clinical decision making in ophthalmic emergencies
Please note there is only ONE correct answer. An answer return form is included in this issue.
It should be completed and returned to: CPD Initiatives (CDM4), Optometry Today,
Victoria House, 178-180 Fleet Road, Fleet, Hampshire GU13 8DA, by May 5, 1999.
1. Which one of the following
statements is incorrect?
Vitreous haemorrhage:
a. may be associated with retinal
detachment
b. may be associated with posterior
vitreous detachment
c. may be caused by diabetic
neovascular proliferation
d. always causes a relative afferent
pupillary defect
2. Which one of the following
statements is correct?
A watery eye and palpable
pre-auricular lymph node
is a common feature of:
a. adenoviral keratoconjunctivitis
b. episcleritis
c. chlamydial conjunctivitis
d. staphylococcal conjunctivitis
3. Which one of the following
statements is incorrect?
Orbital cellulitis:
a. may be secondary to dacrocystitis
b. may be secondary to sinusitis
c. is usually viral in origin
d. may present with proptosis, reduced
ocular movements and optic nerve
compression
4. Which one of the following
statements is incorrect?
Floaters in the field of vision:
a. are always associated with peripheral
visual disturbance
b. may be caused by a posterior
vitreous detachment
c. always require pupil dilation and
comprehensive retinal examination
d. may be caused by posterior uveitis
5. Which one of the following
statements is correct?
a. Bilateral homonymous hemianopia in
the central 15 degrees of vision may
be caused by a temporal lobe
cerebro vascular accident (CVA,
stroke)
b. Left superior homonymous
quadrantanopia may be caused by a
CVA in the right temporal lobe
c. Superior altitudinal field loss in one
eye may be due to a superior branch
retinal artery occlusion
d. Transient ischaemic attacks (TIAs)
affecting the tip of the occipital lobe
may leave a residual field defect
affecting only the central visual field
6. Which one of the following
statements is incorrect?
Alkali injury:
a. causes the pH of intraocular fluids to
fall within seconds of injury
b. should be irrigated with at least 1 litre
of saline or water
c. is potentially more serious than an
equivalent acid injury
d. More serious injury may be
presumed if there is substantial
epithelial loss and ischaemia of the
limbal vessels in the acute phase.
7. Which one of the following
statements is correct?
In anterior uveitis:
a. mutton fat keratic precipitates do not
require investigation for associated
systemic conditions
b. systemic immunosuppression is
always required to allow adequate
control of inflammation in the
long-term
c. intraocular pressure can rise during
acute attacks
d. always gives rise to symptoms of
red eye, photophobia and reduced
vision
8. Which one of the following
statements is incorrect?
The acute management of
central retinal artery
occlusion may include:
a. urgent ESR and CRP
b. anterior chamber paracentesis
c. intravenous acetazolamide
d. isovolaemic haemodilution
9. Which one of the following
statements is incorrect?
Optic nerve compression:
a. may be caused by thyroid eye
disease
b. causes reduction in sensitivity to red
target late in disease
c. causes loss of acuity late in
disease
d. is usually associated with
increasing pain and reduction in
ocular motility
10. Which one of the following
statements is correct?
Relative afferent pupillary
defect:
a. is a feature of homonymous
hemianopia
b. is a common feature of a peripheral
retinal detachment
c. is always symptomatic
d. may be present in an eye with a
normal visual acuity
11. Which one of the following
statements is incorrect?
Retinal detachment:
a. is associated with vitreous
haemorrhage
b. is associated with posterior vitreous
detachment
c. may cause visual field loss
d. causes early loss of acuity
12. Which one of the following
statements is incorrect?
In central retinal artery occlusion,
temporal arteritis:
a. is associated with jaw claudication
and proximal myopathy
b. may have a good visual recovery
if adequate treatment is given rapidly
c. may require a biopsy
for a satisfactory diagnosis
to be made
d. requires treatment with steroids
for a year or more
sponsored by
Multiple choice answers
Here are the correct answers to Part 3 of
Module 1 on Clinical Decision Making,
published on March 12, 1999.
1. Which one of the following statements is correct
regarding the symptoms and signs found in a
posterior vitreous detachment (PVD)?
a. Flashing lights signify a definite retinal tear
b. Floaters and flashing lights are more serious than
floaters alone
c. Pigment cells in the anterior vitreous indicate a high
risk of retinal pathology
d. Floaters always signify a posterior vitreous
detachment
c is correct
In a posterior vitreous detachment, the presence or
absence of flashing lights, in addition to the floaters,
makes no difference with regards to risk of a retinal tear.
Few symptoms may indicate serious pathology.
Examination of the anterior vitreous as it moves may
indicate pigmented cells (Schaeffer’s sign) which are
strongly suspicious of a retinal tear, or other cells
suggesting inflammatory eye disease as the cause of
floaters.
2. Which one of the following
statements is correct regarding central
retinal vein occlusion (CRVO)?
a. Sources of emboli need to be excluded
b. May be caused by hypertension
c. Requires urgent fluorescein angiography
d. Often recovers good visual acuity if treated with
pan-retinal photocoagulation
b is correct
Hypertension is the commonest association with a
CRVO. Other associations include elevated intraocular
pressure and prothrombotic tendencies. Emboli cause
arterial rather than venous occlusions. Fluorescein
angiography may help determine if the CRVO is
ischaemic or not, but is not urgent as the haemorrhages
may obscure the fluorescence acutely and
neovascularisation does not occur immediately. Visual
prognosis after a CRVO is often poor.
3. In the management of age-related macular
degeneration (ARMD), which one of the
following statements is correct?
a. Hard macular drusen signify high risk of sub-retinal
neovascularisation
b. Geographic atrophy requires argon laser
photocoagulation
c. Sudden metamorphopsia requires urgent referral
d. Low vision aids do not benefit patients with
sub-retinal neovascularisation
c is correct
Dry ARMD (drusen, pigmentary changes and
geographic atrophy) is treated conservatively. It is
known that large soft drusen carry a higher risk of subretinal
neovascularisation, of which the earliest sign may
be metamorphopsia. Urgent referral is required if a
patient develops this for consideration of laser or other
treatment. Patients at all stages of ARMD may benefit
from low vision aids.
4. Which one of the following statements is
correct?
Branch retinal artery occlusion (BRAO) -
a. is a result of arteriovenous nipping
b. is caused by chronic open angle glaucoma
c. always results in loss of central vision
d. is often due to an embolus
d is correct
10
APRIL 9 • 1999 OPTOMETRY TODAY

sponsored by
Clinical decision making in ophthalmic emergencies
DISTANCE LEARNING MODULE 1 PART 4
- Clinical management of retinal disorders
A BRAO is usually the result of an embolus,
either from the carotid or cardiac circulation.
AV nipping may result in a branch retinal vein
occlusion as the hypertrophic artery wall
compresses the vein as they cross, and open
angle glaucoma is a risk factor for a central
retinal vein occlusion. The artery occlusion
may affect central vision if it supplies the
macula, or may cause field loss if it supplies
another part of the retina.
5. Which one of the following
statements is correct?
Epi-retinal membrane -
a. always requires surgical correction
b. may cause metamorphopsia
c. is more common in men aged 20-45
d. is always idiopathic
b is correct
An epiretinal membrane may cause
metamorphopsia. It may be idiopathic,
affecting people of both sexes in their 50s and
60s, or be due to other retinal problems such
as post retinal detachment surgery and
cryotherapy. It often stabilises and, therefore,
may require no treatment.
6. Which one of the following retinal
disorders does not present with
floaters?
a. Toxoplasmosis
b. Posterior vitreous detachment
c. Amaurosis fugax
d. Intermediate uveitis
c is correct
The causes of floaters include a posterior
vitreous detachment and inflammatory eye
disease, such as toxoplasmosis and
intermediate uveitis affecting one or both eyes.
Amaurosis fugax causes a transient loss of
vision lasting up to 10 minutes, affecting one
eye.
7. Which one of the following
statements is correct regarding
the management of retinal tears?
a. A retinal tear associated with a retinal
detachment will always be treated with
argon laser only
b. There is always a single retinal tear
after a posterior vitreous detachment
c. Retinal tears may be anterior to the
equator and not visible on slit lamp
biomicroscopy
d. Retinal tears are not treated with
cryotherapy
c is correct
Retinal tears in association with a posterior
vitreous detachment may be anterior to the
equator of the retina and require indirect
ophthalmoscopy with indentation to see. They
may be multiple and can be treated with laser
or cryotherapy. However, if there is an
associated retinal detachment, laser is usually
inadequate and they require detachment
surgery to flatten the detachment and to allow
the laser or cryotherapy to ‘seal’ the tear.
8. Which one of the following
statements is correct?
Macular holes -
a. affect men more commonly than
women
b. may be bilateral
c. require laser treatment
d. often follow on from retinal detachment
surgery or cryotherapy
b is correct
Macular holes typically affect postmenopausal
women and are said to be
bilateral in 10%. They are usually primary or
idiopathic (that is not associated with other
retinal disease) and may require surgery in
the form of vitrectomy and intraocular gas
injection to flatten them.
9. Which one of the following
statements is correct?
Acute central retinal artery occlusion -
a. is treated with intravenous steroids
b. requires attempts to lower the intraocular
pressure
c. always requires laser treatment to prevent
neovascularisation
d. subsequently results in a cupped optic
disc
b is correct
Treatment for a central retinal artery occlusion
is often disappointing, but attempts are made
to move the embolus down the arterial tree by
acutely lowering the intraocular pressure
using ocular massage and intravenous
acetazolamide (diamox). It does not require
laser treatment (unless rubeosis occurs) and
usually results in optic atrophy and severely
reduced vision.
10. Which one of the following
statements is correct?
Photopsia (flashing lights) -
a. last less than 10 minutes in a migraine
attack
b. are usually bilateral in migraine
c. are homonymous in posterior vitreous
detachment
d. are associated with other symptoms in
vertebrobasilar disease
b is correct
Photopsia in migraine last 10-30 minutes and
are usually homonymous and, therefore,
affect both eyes even though most patients
will describe them as unilateral. In posterior
vitreous detachment, they are unilateral and
occur as flickers lasting a few seconds just in
the temporal field of vision in dim light.
Photopsia are not usually associated with
vertebrobasilar disease and would occur with
other symptoms such as vertigo and drop
attacks.
11. Which one of the following
statements is correct regarding
hypertensive retinal
changes?
a. Venous beading and venous
looping are signs of accelerated
hypertension
b. AV nipping occurs as a result of
hypertrophy of the vein wall due
to the hypertension
c. Swollen discs, haemorrhages and
exudates indicate a dangerous
level of blood pressure
d. Silver-wiring is the earliest sign
of hypertension
c is correct
Accelerated hypertension, in which swollen
discs, haemorrhages, cotton wool spots and
exudates are seen, indicates a sudden
severe elevation in blood pressure and
patients require urgent admission for
treatment and to establish the cause, which is
often renal disease. The changes of chronic
essential hypertension include narrowed and
straightened arterioles and AV nipping in
which the thickened artery wall compresses
the vein as they cross. Silver-wiring is not a
good sign of hypertension.
12. Which one of the following does not
require laser treatment?
a. A retinal hole
b. Central retinal vein occlusion
c. Branch retinal artery occlusion
d. Sub-retinal neovascular
membrane
c is correct
Argon laser photocoagulation may be
required to seal around a retinal tear or hole,
to ablate a sub-retinal neovascular membrane
or to prevent rubeosis with pan-retinal
photocoagulation in an ischaemic central
retinal vein occlusion. It is not normally
required in a branch retinal artery occlusion
as the retina distal to this is infarcted, not
ischaemic.
APRIL 9 • 1999 OPTOMETRY TODAY 11